Magic Numbers rule UI cannot be opened (NPE)

[MathiasAugstein]

I cannot add Coding_Problems/MagicNumber rule to our configuration. Using the "Add... ->" Button has no effect, I get the error:

java.lang.NullPointerException
	at net.sf.eclipsecs.ui.config.widgets.ConfigPropertyWidgetFactory.createWidget(ConfigPropertyWidgetFactory.java:57)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.createConfigPropertyEntries(RuleConfigurationEditDialog.java:518)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.createGeneralSection(RuleConfigurationEditDialog.java:173)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.createDialogArea(RuleConfigurationEditDialog.java:127)
	at org.eclipse.jface.dialogs.TitleAreaDialog.createContents(TitleAreaDialog.java:162)
	at org.eclipse.jface.window.Window.create(Window.java:431)
	at org.eclipse.jface.dialogs.Dialog.create(Dialog.java:1094)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.create(RuleConfigurationEditDialog.java:529)
	at org.eclipse.jface.window.Window.open(Window.java:788)
	at net.sf.eclipsecs.ui.config.CheckConfigurationConfigureDialog$PageController.newModule(CheckConfigurationConfigureDialog.java:708)
	at net.sf.eclipsecs.ui.config.CheckConfigurationConfigureDialog$PageController.widgetSelected(CheckConfigurationConfigureDialog.java:514)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:252)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4237)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1060)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4054)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3626)
	at org.eclipse.jface.window.Window.runEventLoop(Window.java:823)
	at org.eclipse.jface.window.Window.open(Window.java:799)
	at net.sf.eclipsecs.ui.config.CheckConfigurationWorkingSetEditor.configureCheckConfig(CheckConfigurationWorkingSetEditor.java:518)
	at net.sf.eclipsecs.ui.config.CheckConfigurationWorkingSetEditor.access$6(CheckConfigurationWorkingSetEditor.java:505)
	at net.sf.eclipsecs.ui.config.CheckConfigurationWorkingSetEditor$PageController.widgetSelected(CheckConfigurationWorkingSetEditor.java:400)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:252)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4237)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1060)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4054)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3626)
	at org.eclipse.jface.window.Window.runEventLoop(Window.java:823)
	at org.eclipse.jface.window.Window.open(Window.java:799)
	at org.eclipse.ui.internal.OpenPreferencesAction.run(OpenPreferencesAction.java:66)
	at org.eclipse.jface.action.Action.runWithEvent(Action.java:474)
	at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:580)
	at org.eclipse.jface.action.ActionContributionItem.lambda$4(ActionContributionItem.java:414)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4237)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1060)
	at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4054)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3626)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1150)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1041)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
	at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:644)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:551)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:156)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:152)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:136)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:401)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:659)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:596)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1467)

Double clicking on the entry opens a dialog that a Null Pointer Exception occured with this error:

java.lang.NullPointerException
	at net.sf.eclipsecs.ui.config.widgets.ConfigPropertyWidgetFactory.createWidget(ConfigPropertyWidgetFactory.java:57)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.createConfigPropertyEntries(RuleConfigurationEditDialog.java:518)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.createGeneralSection(RuleConfigurationEditDialog.java:173)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.createDialogArea(RuleConfigurationEditDialog.java:127)
	at org.eclipse.jface.dialogs.TitleAreaDialog.createContents(TitleAreaDialog.java:162)
	at org.eclipse.jface.window.Window.create(Window.java:431)
	at org.eclipse.jface.dialogs.Dialog.create(Dialog.java:1094)
	at net.sf.eclipsecs.ui.config.RuleConfigurationEditDialog.create(RuleConfigurationEditDialog.java:529)
	at org.eclipse.jface.window.Window.open(Window.java:788)
	at net.sf.eclipsecs.ui.config.CheckConfigurationConfigureDialog$PageController.newModule(CheckConfigurationConfigureDialog.java:708)
	at net.sf.eclipsecs.ui.config.CheckConfigurationConfigureDialog$PageController.doubleClick(CheckConfigurationConfigureDialog.java:500)
	at org.eclipse.jface.viewers.StructuredViewer$1.run(StructuredViewer.java:780)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:174)
	at org.eclipse.jface.viewers.StructuredViewer.fireDoubleClick(StructuredViewer.java:777)
	at org.eclipse.jface.viewers.AbstractTreeViewer.handleDoubleSelect(AbstractTreeViewer.java:1529)
	at org.eclipse.jface.viewers.StructuredViewer$4.widgetDefaultSelected(StructuredViewer.java:1211)
	at org.eclipse.jface.util.OpenStrategy.fireDefaultSelectionEvent(OpenStrategy.java:251)
	at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:308)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	... [same as above from here on]

Currently the MagicNumber rule can neither be added nor changed, only removed.

Using CheckStyle Plugin 8.44.0 on Eclipse 2021-09 (4.21.0)

[cw-eclipse]

Report of issues that may be relevant.

Double-clicking a module will result in a NullPointerException to display the Checkstyle diagnostic rule configuration dialog.

The target is as follows ･Rule category　　　　　　･Rule name Javadoc Comments　　　　AtclauseOrder Coding Problems　　　　　IllegalType Coding Problems　　　　　MagicNumber Coding Problems　　　　　MultipleStringLiterals

Eclipse2021-03 (4.19) CheckStyle 8.44 plugin